So surely there is something which would be superior to grease? Is this only Vesconite?
Redesign the assembly to take some decent recirculating linear ball bearings if we must stick to sliding pillars
And finally, what is the metallurgy which drives wear. Is it simply molecules breaking away slowly and building up an abrasive paste in the grease? (assuming no external agents).
The tribology is very specific to each material combination. There are several mechanisms for wear, abrasion, microscopic welding, microscopic heat, oxidisation so it is difficult to generalise but the “paste” or hard debris can become a problem when it is not flushed out and embeds itself into the surface of the softer matrix.
